A power source includes a generator configured to receive mechanical energy and convert the mechanical energy to an electrical output. The generator includes a rotor and a stator. The stator has a first coil and a second coil. The first coil and the second coil are selectively arranged in a first configuration to provide the electrical output at a first voltage level and in a second configuration to provide the electrical output at a second voltage level. The power source also includes a detection circuit including a sensing relay. The detection circuit is configured to generate an output based on whether the first coil and the second coil are arranged in the first configuration or in the second configuration.